Mobile devices such as cellular telephones, smart phones and other handheld or portable electronic devices such as personal digital assistants (PDAs), headsets, MP3 players, etc. have become popular and ubiquitous. As more and more features have been added to mobile devices, there has been an increasing desire to equip mobile devices with input/output mechanisms that accommodate numerous user commands and/or react to numerous user behaviors. For example, many mobile devices are now equipped not only with buttons or keys/keypads, but also with capacitive touchscreens by which a user, simply by touching the surface of the mobile device and/or moving the user's finger along the surface of the mobile device, is able to communicate to the mobile device a variety of messages or instructions.
It is of increasing interest that mobile devices be capable of detecting the presence of, and determining with some accuracy the position of, physical objects located outside of the mobile devices and, more particularly, the presence and location of human beings (or portions of their bodies, such as their heads or hands) who are using the mobile devices or otherwise are located nearby the mobile devices. By virtue of such capabilities, the mobile devices are able to adjust their behavior in a variety of manners that are appropriate given the presence (or absence) and location of the human beings and/or other physical objects.
Although prior art devices such as capacitive touchscreens are useful as input/output devices for phones, such touchscreens are fairly complicated electronic devices that are expensive and that require a large number of sensing devices that are distributed in location across a large surface area of the phone. Also, such touchscreens are limited insofar as they only allow a user to provide input signals if the user is actually physically touching the touchscreens. Further, while remote sensing devices such as infrared (or, more accurately, near-infrared) transceivers have been employed in the past in some mobile devices to allow for the detection of the presence and/or location of human beings and/or physical objects even when not in physical contact with the mobile devices, such sensing devices have been limited in various respects.
In particular, some such transceivers in some such mobile devices are only able to detect the presence of a human being/physical object within a certain distance from the given transceiver (e.g., detect that the human being/physical object is within a predetermined distance or proximity to the transceiver), but not able to detect the three-dimensional location of the human being/physical object in three-dimensional space relative to the transceiver. Also, some such transceivers in some such mobile devices are undesirably complicated or require large numbers of components in order to operate, which in turn renders such devices unduly expensive.
Therefore, for the above reasons, it would be advantageous if a new sensing device or sensing devices suitable for one or more types of mobile devices could be developed that overcame one or more of the above-described limitations, and/or one or more other limitations.